Pinball Tracking System

ABSTRACT

An entertainment device typically described as a pinball machine, usually found in myriad places such as arcades, restaurants, private residences, etc. A conventional pinball machine allows one or more players to play a game in which points are accrued by physically striking one or more balls on an inclined play field within a cabinet having a transparent top surface. Interaction of the machine with the ball is typically limited to events when the ball strikes an object on the play field. To enable more machine-ball interaction and therefore increase entertainment value ball tracking is needed. A way to track the ball in a very fast manner to better enable open space interactivity while not having excessive cost and while not limiting the game designer.

FIELD OF THE INVENTION

The present disclosure relates generally to gaming devices, and morespecifically, to pinball machines with playfields containing an openspace.

BACKGROUND AND SUMMARY OF THE INVENTION

A pinball machine is an entertainment device usually found in myriadplaces such as arcades, restaurants, private residences, etc. Aconventional pinball machine allows one or more players to play a gamein which points are accrued by physically striking one or more balls onan inclined playfield within a cabinet having a transparent top surface.Commonly, the balls used in play are smooth steel and have a reflectivespherical surface.

The pinball machine's playfield typically includes one or more physicaltargets. When a ball strikes a particular physical target, anelectromechanical switch coupled to (or otherwise integrated into) thetarget detects the mechanical impact, which then triggers a change insome aspect of the game. For example, in some cases, when a ball hits agiven target, a player may score a predetermined amount of points.

In most pinball implementations, a “drain” is located at the bottomportion of the playfield. Usually, if the ball falls into the drain, thegame ends or another ball is provided to the player. Mechanical“flippers” capable of at least partially covering the drain may allow askilled player to hit the ball at an appropriate time so as to preventit from falling into the drain, thus putting that same ball back in playand extending the duration of the game.

Between the pinball machine's physical targets and the drain isgenerally an open playfield that contains no obstructions for the ball.This open area commonly contains graphics and visually interestingcontent such as lights or a display for entertaining purposes. It alsocan contain sensors such that when the ball passes over a specific placethe sensor is triggered, and the computer can take an action. However,there is generally very little ball interaction in the open area playfield on typical machines. Currently, the prior art demonstrates a touchscreen display embedded in this open space that can detect the ball asit traverses but the reaction time is much too slow to enableinteractivity and the cost can be excessive in larger instantiations.Likewise, an array of emitters and receivers can line the edge of theplay field to provide ball location, but this method severely limits thegame designer in placement of the interactive elements that characterizethe game of pinball.

A way to track the ball in a very fast manner to better enable openspace interactivity while not having excessive cost and while notlimiting the game designer is needed to move the field of pinball gamedesign forward.

The background description provided herein is for the purpose ofgenerally presenting the context of the disclosure. Work of thepresently named inventors, to the extent it is described in thisbackground section, as well as aspects of the description that may nototherwise qualify as prior art at the time of filing, are neitherexpressly nor impliedly admitted as prior art against the presentdisclosure.

SUMMARY

In summary, the present disclosure relates to a pinball machine.

BRIEF DESCRIPTION OF THE DRAWINGS

The detailed description set forth below references the followingdrawings:

FIG. 1 shows a top-front view of a prior art package for a pinballmachine with a ball tracking function.

FIG. 2 is a top-front view of a pinball machine containing two upwardlooking cameras used to locate ball position according to an exemplaryembodiment of the present disclosure;

FIG. 3 is a top-front view of a pinball machine containing two downwardlooking cameras used to locate ball position according to an exemplaryembodiment of the present disclosure;

FIG. 4 is a top-front view of a pinball machine containing one downwardlooking camera used to locate ball position according to an exemplaryembodiment of the present disclosure;

FIG. 5 is a side view of a camera mounted to a pinball play fieldaccording to an exemplary embodiment of the present disclosure;

FIG. 6a illustrated a means for calibrating the camera's ball locationability according to an exemplary embodiment of the present disclosure;

FIG. 6b illustrates the image seen by the camera shown in FIG. 6aaccording to an exemplary embodiment of the present disclosure;

FIG. 7 illustrates the means for finding the location of the ball withtwo cameras according to an exemplary embodiment of the presentdisclosure;

FIG. 8a illustrates the image seen by a first camera shown in FIG. 7according to an exemplary embodiment of the present disclosure;

FIG. 8b illustrates the image seen by a second camera shown in FIG. 7according to an exemplary embodiment of the present disclosure;

FIG. 9 illustrates the means for finding the location of the ball withone camera according to an exemplary embodiment of the presentdisclosure; and

FIG. 10 illustrates the image seen by the camera in FIG. 9.

DETAILED DESCRIPTION

The present disclosure, as demonstrated by one of several exemplaryembodiments described below, can provide a means to track a pinball in afast manner in the open space of a pinball machine to better enableinteractive play without encumbering the game designer or exceeding costtargets.

In the first exemplary embodiment, at least two small digital camerasare installed on the play field pointed horizontally such that the ballis in the field of view of one or more of the cameras as it passes by.Each camera views a section of the field from a different angle. On eachside of each camera is mounted at least one infrared light emittingdiode (LED) having a wavelength between 800 nm and 1000 nm preferablybetween 840 nm and 860 nm. In some configurations the cameras can shareone or more LEDs. Each camera contains a lens system having a materialthat reflects all visible light, only allowing infrared to betransmitted and picked up by the camera. Each camera takes still shotsat a rate between 5 frames per second (fps) and 60 fps or, morepreferably, at a rate between 10 fps and 30 fps. Not all cameras mustoperate at the same frame rate. The frame rate can be substantiallyfaster in other embodiments.

The Infrared light emitting diodes (LEDs) proximate to each camera flashat the right time during the exposure for the camera to capture lightfrom the LEDs reflected off the surface of the ball. The computingsystem captures an image from at least two cameras and, per anapplication specific algorithm, searches through them to find thehorizontal position of the ball. The algorithm then further specifiesthat the ball's absolute X-Y coordinate is calculated with respect tothe mounting position of each camera by taking into account thehorizontal position of the ball in each camera view as well as thephysical geometric relationship of the cameras to one another.

Vertical calibration can be done automatically with information on theplay field by observing the location of other reflective objects such asa post supporting an interactive play feature. In some embodiments, animage of the background could be stored and subtracted from the runningimage to reject background reflections. The image of the ballreflections in the camera have a curved feature. Other reflectivesurfaces on the field can be sorted out because they are generally linescoming from reflections of cylinders or rectangular objects.

In yet another exemplary embodiment, the system can contain only onecamera of the type described above that is configured to view thepinball in one area inside the pinball machine. In this embodiment, atleast two Infrared LEDs are mounted, at least one on each side of thecamera and each LED located at least one inch away from another LED.Because the surface of the ball is spherical, multiple reflections canbe captured by the computing system in one image from the one camera.Based on the centroid location of the duplicate reflection in the imageand the distance between the two reflections, the X-Y position can becomputed.

In a third exemplary embodiment, at least two cameras of the abovedescribed type can be used as before but without the LEDs mounted nearthe cameras. In this embodiment, one or more LEDs are mounted oppositeof the cameras such that the camera is flooded with Infrared light fromthe LEDs. When the ball passes by, a round silhouette is observed ineach of the camera images captured by the computing system.

In a fourth exemplary embodiment a single camera can be enabled to trackthe pinball location by viewing the entire ball reflection as a solidcircle based on a single Infrared light source. The diameter of the ballin the image is then an indication of how far away from the camera theball is when the image was captured while the position of the pinball inthe reflection is an indicator of the position of the ball in a seconddimension. Together, these two pieces of information can be used todetermine the 2D position of the pinball. The modern pinball gameindustry has standardized on a 1.0625″ diameter pinball so the samemethod can work across multiple games.

It should be understood that the term camera can be understood to beseveral different Infrared light detection schemes. By way of example,the term camera can mean an array of individual Infrared detectors suchas Infrared transistors either separately packaged or packaged in thesame silicon die. The term camera can also refer to the common meaningof a digital camera like the camera found in the modern smart phone.More generally, the term camera refers any device that is sensitive toInfrared light in a way that enables the system in the presentdisclosure to “see” the reflection of the ball.

One skilled in art of computing systems will realize that a computingsystem is enabled by an algorithm that specifies a set of actions totake place in order to accomplish the tracking of the ball. One suchalgorithm that can be associated with at least one of the embodiments inthe present disclosure can be defined as follows; 1) the computingsystem collects an image from the first camera by illuminating anassociated LED while at the same time triggering the capture of theimage from the first camera, 2) the computing system collects an imagefrom the second camera by illuminating an associated LED while at thesame time triggering the capture of the image from the second camera.The first two steps can take place serially or simultaneously, 3) thecomputing system locates the ball's location within each image, 4) thelocation of the ball in each image is used to calculate the ball's X-Yposition based on known stereo-optics equations and the physicallocation of the cameras to one another, and 5) the ball's X-Y locationis then acted upon based on the prescribed desires of the game'sdesigner. The algorithm can loop indefinitely or can be triggered to runbased on an internal or external trigger.

The pinball machines manufactured at the present are lit with LEDs thatemit light in the visible spectrum and so there is only backgroundinfrared light from outside of the pinball machine to interfere with thesystem. Some, or all, of this background light is reflected by the glasscovering the playfield. In the event that the glass covering theplayfield does not prevent all background light from entering the fieldof view of the camera, a small opaque shield can cover the topside ofthe camera lens to limit the field of view of the camera so as toeliminate any background interfering light. Similarly, a digitalfiltering approach can be made use of by subtracting the light capturedby the camera during a portion of play where there is no Infrared lightgenerated by the lights associated with the camera. This backgroundlight measurement can be used to calibrate out any interfering lightthereby increasing the accuracy of the system. Any, or all, of thesebackground light eliminating means can be used together or separately.

The optics that are a part of the lens system in the camera remove allvisible light resulting in an image that is simple to process and findthe ball. This greatly reduces the processing power and cost comparedwith a typical computer vision system. Based on calibration, the camerasonly need to sample a small horizontal slice of the viewing area whichleads to further processing speed improvements.

It should be understood that a single pinball game can make use ofvarious different described embodiments herein at the same time tocreate a pinball following feature across multiple areas on the playfield. By way of example, two cameras could be used near the flippers tofollow the ball in the open play field while a single camera could bemounted in the upper area near the play field features to observe theball as it passes through. Likewise, multiple embodiments of the presentdisclosure can be used in conjunction to view the ball in the sameportion of the playfield to increase the accuracy of the overall balltracking system.

Furthermore, one skilled in the art will recognize that the cameras canbe mounted on the playfield such that the viewing angle is substantiallyparallel with the playfield or equivalently they can be mounted belowthe playing surface such that the viewing angle is substantiallyperpendicular to the playfield along with an Infrared reflective devicemounted such that the light path is altered from substantially parallelto the playfield to substantially perpendicular to the playfield. Thisreflective device can be as simple as a mirror or a more complicatedspherical reflective surface that permits a larger field of view. Thiscomplicated reflective surface can even act to permit a 360 degree viewfor the camera located under the playfield. Additionally, the camera canbe mounted under the playfield constructed of an Infrared transmissivematerial surface. In such a configuration, the Infrared light can passthrough the playing surface and be observed by the camera underneath.

In further embodiments, these aforementioned camera-based systems can beused to replace one or more roll-overs; mechanical devices (or inductivesensors in some systems) that trigger when the pinball rolls over them.These roll-overs are used, for example, to start new modes, activatelights, and accrue points. The pinball vision system can replace thecommon roll over entirely by simply computing the X-Y position of theball and comparing it to a pre-defined roll-over region in the game.When the ball is in the pre-defined region it initiates the sameresponse as if a mechanical switch was actuated. Furthermore, any andall visible lights on the playfield can be enabled to interact with thepassing of the ball. These lights are commonly used to indicate score,announce goals, and entertain the player.

As an example of the interactivity enabled by the system, an under fieldlight matrix can exist across the entire play field or a subset of theplayfield. As the ball passes over the top of the light it can be turnedoff by the computing system. The goal for the player can be to get allthe lights off. Alternatively, the field light matrix can be used toenable path tracing of the ball as it passes over the lights either bylighting up all lights not in the path of the ball or lighting up alllights in the path of the ball. This under field light matrix can be asimple matrix of individual lights or a visual display screen such asthe common liquid crystal display (LCD) screen.

The light matrix can function in myriad ways including the path tracingas above or color changing in the context of a multi-color light matrix.As the score advances past a threshold or the game changes play mode,the color of the ball's path can change or more generally the lightmatrix can interact differently with the ball.

Now enabled by the present disclosure is an ability to create aself-play mode wherein the pinball machine can actuate its own flippersto keep a ball in play. This can be advantageous for several reasonsincluding the use of an attraction-mode or a type of life-line for aplayer to use during the game. In the attraction-mode the machine canplay the ball itself to show action taking place to draw a player intothe game that may be just passing by. In the life-line scenario, aplayer may buy or earn the use of a machine-assist mode for a presetamount of time or preset number of flipper contacts wherein the machinewould do the work of actuating the flippers at the right time. Thismachine-assist mode could be initiated by the player pressing a buttonor by the player hitting a specific target on the playfield.

Furthermore, the self-playing machine can be enabled with a learningdatabase such that a type of artificial intelligence system can bebuilt. This system can learn the proper timing to strike the ball withflipper to hit a specific target. Since each machine is located on aspecific slope and has specific and changing response timing to itsactuators, the learning database can be used to account for theseunknowns and changing variables.

Additionally, the above described system can track more than one ball inplay at the same time. With two balls in play at the same time therecould be possibility of a ball collision on the play field which couldbe observed by the tracking system and rewarded in game play.Alternatively, one of the balls could be captive in position on theplayfield and if a collision took place between the ball in play and thestationary ball, the tracking system could reward the player.

Play field objects that might otherwise include mechanical switches todetect ball hits would no longer require those switches, wires, andassociated maintenance. Each object hit can be detected by the ballposition, ball motion vector, and the change in the ball vector causedby the collision.

Turning now to the drawings, FIG. 1 illustrates the prior art pinballmachine designated generally by the reference numeral 150. The pinballmachine 150 in FIG. 1 is enabled to track the position of the ballduring play. The pinball machine 150 includes a cabinet 101 which housesa playfield 103 which may be inclined. Generally, the cabinet 101 hasmounted atop a score display 100. The playfield 103 supports a gamepiece such as a rolling ball 110 and has a plurality of playfieldfeatures and devices as well as a generally open area 104 where nothinginterferes with the rolling of the ball because nothing is in the way toimpede its travel. These features and devices may take a number of formsand some relatively simplified play features are targets 102A, 102B,102C, 102D, and 102E and bumpers 106A and 106B. The ball 110 may beinitially introduced into the playfield 103 by shooting the ball 110with a plunger element 114. If the playfield 103 is inclined the balltends to roll back generally in the direction of a pair of flippers 108Aand 108B located at a bottom end part of the playfield 103. The flippers108A and 108B, which are activated by buttons 112A and 112B on the sidesof the cabinet 101, are used by the skilled player to propel the ballback into the playfield 103. The playfield 103 contains a touch screen116 enabled to track the ball's position during play based on thephysical contact between the ball 110 and the screen 116. The physicalcontact can be pressure caused by gravity or by the capacitive orinductive nature of the ball 110. Inherently, screen 116 is expensiveand takes significant computing power to enable ball tracking. Even thenthe ball tracking performed is slow and does not allow the level ofinteractivity desired. The playfield devices and features may include anumber of elements not shown in FIG. 1.

FIG. 2 illustrates an exemplary embodiment of the present disclosure.The pinball machine 250 in FIG. 2 is enabled to track the position ofthe ball during play using the methods of the present disclosure. Thepinball machine 250 includes a cabinet 201 which houses a playfield 203which may be inclined. Generally, the cabinet 201 has mounted atop ascore display 200. The playfield 203 supports a game piece such as arolling ball 210 and has a plurality of playfield features and devicesas well as a generally open area 204 where nothing interferes with therolling of the ball because nothing is in the way to impede its travel.These features and devices may take a number of forms and somerelatively simplified play features are targets 202A, 202B, 202C, 202D,and 202E and bumpers 206A and 206B. The ball 210 may be initiallyintroduced into the playfield 203 by shooting the ball 210 with aplunger element 214. If the playfield 203 is inclined the ball tends toroll back generally in the direction of a pair of flippers 208A and 208Blocated at a bottom end part of the playfield 203. The flippers 208A and208B, which are activated by buttons 212A and 212B on the sides of thecabinet 201, are used by the skilled player to propel the ball back intothe playfield 203. The playfield 203 further contains camera modules216A and 216B wherein camera module 216A contains a field of viewbounded by edges 218A and 218B and camera module 216B contains a fieldof view bounded by edges 218C and 218D. It should be understood herethat camera modules 216A and 216B contain all critical elementsnecessary to enable the functionality of the system including but notlimited to a lens system, a digital camera, a visible light filter,integrated electronics enabled to transmit data either by wired orwireless interface, and an illumination device such as one or moreInfrared LEDs. If the edges 218A, 218B, 218C, and 218D are extended, aregion is formed where both camera modules 216A and 216B can view theball. It is in this shared region that the two-camera tracking system isenabled to track the ball 210. Through the camera module's 216A and 216Bconnection to pinball computing system 220, this system is enabled by analgorithm to track the ball's position during play based on the presenceof the ball 210 in the field of view of camera modules 216A and 216B.The playfield devices and features may include a number of elements notshown in FIG. 2. Numerous features, not shown, can be connected tocomputing system 220 such that the numerous features can be controlledby computing system 220 based on the current location or path of ball210. For example, these features could include lights, light matrices,display screens, actuators, and speakers.

FIG. 3 illustrates a second exemplary embodiment of the presentdisclosure. The pinball machine 350 in FIG. 3 is enabled to track theposition of the ball during play using the methods of the presentdisclosure. The pinball machine 350 includes a cabinet 301 which housesa playfield 303 which may be inclined. Generally, the cabinet 301 hasmounted atop a score display 300. The playfield 303 supports a gamepiece such as a rolling ball 310 and has a plurality of playfieldfeatures and devices as well as a generally open area 304 where nothinginterferes with the rolling of the ball because nothing is in the way toimpede its travel. These features and devices may take a number of formsand some relatively simplified play features are targets 302A, 302B,302C, 302D, and 302E and bumpers 306A and 306B. The ball 310 may beinitially introduced into the playfield 303 by shooting the ball 310with a plunger element 314. If the playfield 303 is inclined the balltends to roll back generally in the direction of a pair of flippers 308Aand 308B located at a bottom end part of the playfield 303. The flippers308A and 308B, which are activated by buttons 312A and 312B on the sidesof the cabinet 301, are used by the skilled player to propel the ballback into the playfield 303. The playfield 303 further contains cameramodules 316A and 316B wherein camera module 316A contains a field ofview bounded by edges 318A and 318B and camera module 316B contains afield of view bounded by edges 318C and 318D. It should be understoodhere that camera modules 316A and 316B contain all critical elementsnecessary to enable the functionality of the system including but notlimited to a lens system, a digital camera, a visible light filter,integrated electronics enabled to transmit data either by wired orwireless interface, and an illumination device such as one more InfraredLEDs. If the edges 318A, 318B, 318C, and 318D are extended, a region isformed where both camera modules 316A and 316B can view the ball. It isin this shared region that the two-camera tracking system is enabled totrack the ball 310. Through the camera module's 316A and 316B connectionto pinball computing system 320, this system is enabled by an algorithmto track the ball's position during play based on the presence of theball 310 in the field of view of camera modules 316A and 316B.Furthermore, computing system 320 is connected to buttons 312A and 312Bsuch that the computing system 320 can actuate flippers 308A and 308Bthereby enabling pinball machine 350 with a self-play mode. Thecomputing system 320 connection to buttons 312A and 312B is completed insuch a way that allows both the player and the computing system 320 toactuate flippers 308A and 308B as desired. The playfield devices andfeatures may include a number of elements not shown in FIG. 3. Numerousfeatures, not shown, can be connected to computing system 320 such thatthe numerous features can be controlled by computing system 320 based onthe current location or path of ball 310. For example, these featurescould include lights, light matrices, display screens, actuators, andspeakers.

FIG. 4 illustrates a third exemplary embodiment of the presentdisclosure. The pinball machine 450 in FIG. 4 is enabled to track theposition of the ball during play using the methods of the presentdisclosure. The pinball machine 450 includes a cabinet 401 which housesa playfield 403 which may be inclined. Generally, the cabinet 401 hasmounted atop a score display 400. The playfield 403 supports a gamepiece such as a rolling ball 410 and has a plurality of playfieldfeatures and devices as well as a generally open area 404 where nothinginterferes with the rolling of the ball because nothing is in the way toimpede its travel. These features and devices may take a number of formsand some relatively simplified play features are targets 402A, 402B,402C, 402D, and 402E and bumpers 406A and 406B. The ball 410 may beinitially introduced into the playfield 403 by shooting the ball 410with a plunger element 414. If the playfield 403 is inclined the balltends to roll back generally in the direction of a pair of flippers 408Aand 408B located at a bottom end part of the playfield 403. The flippers408A and 408B, which are activated by buttons 412A and 412B on the sidesof the cabinet 401, are used by the skilled player to propel the ballback into the playfield 403. The playfield 403 further contains cameramodule 416 having a field of view bounded by edges 418A and 418B.Located near camera module 416 are two Infrared LEDs 422A and 422Benabled to illuminate the field of view of camera module 416. It shouldbe understood here that the camera module 416 contains all criticalelements necessary to enable the functionality of the system includingbut not limited to a lens system, a digital camera, a visible lightfilter, and integrated electronics enabled to transmit data either bywired or wireless interface. Through the camera module's 416 connectionto pinball computing system 420 and the connection of LEDs 422A and 422Bto the same computing system 420, this system is enabled by an algorithmto track the ball's position during play based on the presence of theball 410 in the field of view of the camera module 416. The playfielddevices and features may include a number of elements not shown in FIG.4. Numerous features, not shown, can be connected to computing system420 such that the numerous features can be controlled by computingsystem 420 based on the current location or path of ball 410. Forexample, these features could include lights, light matrices, displayscreens, actuators, and speakers.

FIG. 5 illustrates a side-view of a camera module mounted in the playingsurface. Playfield 502 has mounted to it a bracket 508 which furthermounts to backplate 506. These three elements provide the physicalstructure to hold camera 500 steady during play. Further, an LED 504 canbe mounted to the same backplate 506 or can mount to a secondarystructure. Finally, signal generating and routing module 510 alsoconnects to the same backplate 506 and acts to route the electricalsignals to and from the camera 500 and LED 504 including anypre-processing and to communicate the required image data back to acentral computing system (not shown). Backplate 506 can be a metalbracket, a printed circuit board, or any combination thereof. FIG. 5illustrates only one preferred embodiment for inserting a camera moduleinto the playfield 502. Several other means are possible includingmounting to the top surface of playfield 502, mounting below the topsurface of playfield 502 combined with a mirror, or mounting belowplayfield 502 wherein playfield 502 is constructed of Infraredtransmissive material.

FIG. 6a illustrates a top view of the camera to understand a means forcalibrating the camera according to the present disclosure. Camera 600is shown with a precisely known location with respect to an X axis 608and a Y axis 610 having a cartesian coordinate system with an origin606. Camera 600 has an X axis 608 location 620 and a Y axis 610 location622. Also illustrated are two playfield features 602 and 604. Thesefeatures 602 and 604 are stationary objects that can be used by camera600 to calibrate the image taken by using a series of pre-programmedgeometric equations that would be entirely dependent on the game at handand the position of the camera with respect to the features. Feature 604has an X axis 608 location 618 and a Y axis 610 location 624. Feature602 has an X axis 608 location 616 and a Y axis 610 location 626.Furthermore, camera 600 has an angle of orientation with respect tofeatures 602 and 604. The angle of orientation is defined with respectto the Y axis 610 such that the left edge of the field of view of camera600 is defined by a parallel line 628 to Y axis 610. The location of thefeatures 602 and 604 are further defined by angles 612 and 614respectively wherein angle 612 is the angle between the field of viewedge 628 and the image vector 630 of feature 602 and angle 614 is theangle between the field of view edge 628 and the image vector 632 offeature 604.

FIG. 6b illustrates the camera's view as outlined in FIG. 6a . Here,camera view 650 contains a field of view edge 656 and two reflections652 and 654 wherein reflection 652 is associated with the feature 604from FIG. 6a and reflection 654 is associated with the feature 602 fromFIG. 6a . Reflection 652 has a position in the image that is a number ofpixels 658 away from the field of view edge 656 while reflection 654 hasa position in the image that is a number of pixels 660 away from thefield of view edge 656. The number of pixels 658 and 660 can be used inconjunction with the geometry of FIG. 6a to compute the specificcalibration of the camera with respect to its location inside thepinball game playfield. It will be recognized by one skilled in the artthat each camera will have its own playfield features that will becaptured in a calibration image and the required computations will bespecific to each camera and its location. By way of example, one cameramay have three playfield features located at varying distances from thecamera while a second camera may have four playfield features at equaldistance from the camera. In some cases, more than one camera can usethe same set or partially the same set of playfield features tocalibrate from. In this case the two cameras can calibrate theirpositions with respect to one another.

Furthermore, it would be recognized by one skilled in the art that it ispossible to manufacture the game with the disclosed system wherein thecalibration means is simply pre-programmed into the system based on thepredetermined location of all the objects. Alternatively, thecalibration can be accomplished by taking the ball and positioning it ina series of known locations around the playfield and in view of thecamera being calibrated. In each position the system is able to adjustthe image position to correspond to the ball's predetermined location.Furthermore, instead of adjusting the image to correspond to the ball'spredetermined location, the camera position or angle can be adjustedsuch that the ball's predetermined location corresponds to the imagewithout adjusting the image. Likewise, any element on or near theplayfield can be physically adjusted to interact with the passing ballat the proper time and location. By way of example, a light grid locatedon the playfield surface can be adjusted on the 2D surface to correspondwith where the ball is understood to be by the system. In this way, aray-tracing light grid can be easily calibrated to be visually accurateto the player.

FIG. 7 illustrates a ball location method with two cameras. Cameras 700and 702 are shown with precisely known locations with respect to an Xaxis 708 and a Y axis 710 having a cartesian coordinate system with anorigin 706. Camera 700 has an X axis 708 location 726 and a Y axis 710location 716 while camera 702 has an X axis 708 location 722 and a Yaxis 710 location 718. FIG. 7 additionally includes two Y axis 710parallels 728 and 730 for reference purposes. Also illustrated is theball 704. Ball 704 has an X axis 708 location 724 and a Y axis 710location 720. Ball 704 is in the field of view of both cameras 700 and702 such that the image vector 732 of camera 700 is at an angle 712 withrespect to the Y axis parallel 728 while the image vector 734 of camera702 is at an angle 714 with respect to the Y axis parallel 730. Oneskilled in the art will realize that the geometric computations willdepend on the specific orientation of the cameras and their proximity toone another.

FIG. 8a illustrates the view of the camera 700 from FIG. 7. A ghostimage of ball 804A is shown only for illustrative purposes as it doesnot show up in the actual image 802A of the camera. Reflection 806A isfound in the image from the camera located a distance 810A from the leftedge 808A of the image.

FIG. 8b illustrates the view of the camera 702 from FIG. 7. A ghostimage of ball 804B is shown only for illustrative purposes as it doesnot show up in the actual image 802B of the camera. Reflection 806B isfound in the image from the camera located a distance 810B from the leftedge 808B of the image.

Together the images in FIGS. 8a and 8b are processed to determine thespecific distances 810A and 810B and based on the pre-calibratedpositions of the cameras and their associated orientations, the locationof ball 804A,B can be understood very quickly. It should be understoodthat FIGS. 8a and 8b constitute one frame from each camera and that thisprocess of computing the ball location can take place as fast as 60times per second such that the ball location is known every 16.7 ms.

Furthermore, with such accuracy and speed, the same computing system cangenerate a path that the ball is traveling and thereby causeinteractions to take place. Additionally, since the frame rate of thecameras are controlled, the computing system can also understand notonly where the ball has been but where it is projected to be both basedon learning the slope of the machine in its installed location and byunderstanding a predefined vector of the ball, its mass, and expectedrolling resistance on the playfield.

FIG. 9 illustrates a single camera method for determining a ballposition on the playfield. Camera 900 is flanked by LEDs 902 and 904.LED 902 emits light in a cone that contains light vector 908 whichreflects off the ball 906 and travels into the camera 900 lens viavector 910. LED 904 emits light in a cone that contains light vector 912which reflects off the ball 906 and travels into the camera 900 lens viavector 914.

FIG. 10 illustrates the image seen by the camera in FIG. 9. Field ofview 1000 is quite large but even though the camera is capable ofcapture such a large image the computing system can ignore all portionsof the image outside of window 1002 because the ball 1004 (ghost imagedhere as it doesn' t actually show up in the image) is known to betraveling on the surface of the playfield and therefore cannot existoutside of window 1002. In this window 1002 the centroid 1014 ofreflections 1006 and 1008 is observed to be a number of pixels 1010 awayfrom left window edge 1012. Furthermore, reflections 1006 and 1008 arefound to be a number of pixels 1016 away from one another. Based on thenumber of pixels 1010 and 1016 the position of the ball 1004 withrespect to the camera capture the image 1000 can be known by taking intoaccount the pre-calibration geometry and associated values.

While the present disclosure has been described with reference to anexemplary embodiment, it will be understood by those skilled in the artthat various changes may be made and equivalents may be substituted forelements thereof without departing from the scope of the presentdisclosure. In addition, many modifications may be made to adapt aparticular situation or material to the teachings of the presentdisclosure without departing from the essential scope thereof.Therefore, it is intended that the present disclosure not be limited tothe particular embodiment disclosed as the best mode contemplated forcarrying out this present disclosure, but that the present disclosurewill include all embodiments falling within the scope of the appendedclaims. The right to claim elements and/or sub-combinations that aredisclosed herein as other present disclosures in other patent documentsis hereby unconditionally reserved.

What is claimed is:
 1. A pinball tracking system as set forth hereinutilizing optical sensors such as cameras under the devices glasscovering.
 2. A pinball tracking system comprising: a first cameraenabled to capture a first Infrared reflected view of a pinball, whereinsaid camera is further coupled with at least one first Infrared LED; asecond camera enabled to capture a second Infrared reflected view of thepinball, wherein said second camera is further coupled with at least onesecond Infrared LED; and a computing system coupled to said first cameraand said second camera enabled with a ball tracking algorithm to processthe first Infrared reflected view and the second Infrared reflectedview, wherein said algorithm is enabled with a pre-defined geometricrelationship between the first camera, the second camera, and aplayfield such that the pinball location can be computed with respect tothe playfield.
 3. The pinball tracking system of claim 2 wherein saidcomputing system is further enabled to sequence repeatedly to processthe first Infrared reflected view and the second Infrared reflected viewsuch that the computing system can compute a path of said pinball. 4.The pinball tracking system of claim 3 wherein said computing system ispre-configured with information about stationary objects on theplayfield used to continuously calibrate the system and reporting of theball position.
 5. A pinball tracking system comprising: at least onecamera each enabled to capture an Infrared reflected view of a pinball,wherein said each at least one camera is further coupled with at leasttwo Infrared LEDs separated by a distance of at least one inch; and acomputing system coupled to said at least one camera enabled with a balltracking algorithm to process the Infrared reflected view from each atleast one camera, wherein said algorithm is enabled with a pre-definedgeometric relationship between the at least one camera and a playfieldsuch that the pinball location can be computed with respect to theplayfield.
 6. The pinball tracking system of claim 5 wherein saidcomputing system is further enabled to sequence repeatedly to processthe Infrared reflected such that the computing system can compute a pathof said pinball.
 7. The pinball tracking system of claim 6 wherein saidcomputing system is pre-configured with information about stationaryobjects on the playfield used to continuously calibrate the system andreporting of the ball position.